Refrigeration system charging apparatus



Feb- 14, 1967 w. v. MILLER I-:TAL 3,303,563

REFRIGERATION SYSTEM CHARGING APPARATUS Filed OGC. 20, 1965 FIG. Iv

William V. Miller und M Robert A. Essig ATTORNEY United States Patent 3,303,663 REFRIGERATION SYSTEM CHARGING APPARATUS Wiiliarn V. Miiier, South Amherst, and Robert A. Essig,

Elyria, Ohio, assignors to Luxaire, Enc., Elyria, Ohio, a

corporation of Ohio Filed Get. 20, 1965, Ser. No. 498,923 3 Claims. (Cl. 62-149) The present invention relates to refrigeration systems of the expansion type and more particularly to apparatus for predeterm-ining the charge or amount of refrigerant in an operating refrigeration system.

Expansion refrigeration systems of the type having a compressor, a condensing coil, an expansion valve or capillary tube, and an evaporatng coil containing a refrigerant cycling `back and forth from liquid or semiliquid to gaseous states in a sealed system are well known. Such systems may be normally vcharged with a predetermined amount of refrigerant at the factory and then sealed, although gage ports are usually provided through which refrigerant may lbe added or removed from the syst-em. Such systems employing capillary tubes instead of expansion valves require rather precise control of the amount or charge of the refrigerant for best operation under given conditions of use. All of the refrigeration systems referred to may require changes in the refrigrant charge because of the ambient conditions of use encountered in the field or because of usage over a long period of time. Also, the amount of piping in a refrigeration system may not be finally determined until the system is installed so that the charge of refrigerant in the system must be adjusted after .installation in Vaccordance with the actual amo-unt of piping used. The need for a change in the charge of refrigerant in such a cooling system may be indicated in various ways such as by the temperature pressure characteristics of the refrigerant in the suction line to the compressor, or by the temperature pressure characteristics of the refrigerant in the liquid line and these indications may be variable under different actual or ambient conditions of operation.

It is a principal object of the present invention to provide apparatus for automatically predetermining the charge of a normally sealed expansion refrigeration systern during its operation to obtain a desired condition of operation as may be indicated by the temperature pressure characteristics of the refrigerant at various points in the system.

Another object of the present invention is to provide apparatus for automatically changing the charge of refrigerant in a normally sealed expansion refrigeration syste-m during its operation to obtain a charge of refrigerant in the system that will produce a desired temperature pressure characteristic of refrigerant in either the suction line or the liquid line in the refrigeration system for the ambient conditions encountered during the then operation of the system.

In a simplified form of the invention, the charging apparatus is comprised of a thermostatic controlled, inlet valve having an intake port adapted to be connected to a source of refri-gerant charge under relatively high pressure and an outlet port adapted to be connected to the gage port in the suction line of the operating cooling system whose refrigerant charge is to be predetermined during operation. The thermal control bulb or element for the inlet valve is adapted to be connected in temperature sensing relation to the cooling system suction l-ine. Also, the pressure responsive control ele-ment of the thermostatic inlet valve is connected to its outlet and therefore the suction line of the cooling system to sense the refrigerant pressure in such line. Assuming the charge of refrigerant in the cooling syste-rn to be low, in acice cordance with the invention, the thermostatic inlet valve is calibrated and arranged to be open under such conditions to permit refrigerant from the source to enter the cooling system through the gage port during operation of the cooling system until the temperature pressure relation for the refrigerant charge in the cooling system suction line reaches a desired value indicative of the correct charge of refrigerant. This same form of the invention may -be slightly modified to include a controlled leak to the atmosphere from the outlet o-f the thermostatic inlet valve that is connected to the suction line of the refrigeration system so that `an excess amount of the refrigerant charge in the suction line may be bled off until the inlet valve o-pens to recharge the system to the desired amount of charge at which time the bleed land the charge may balance each other. Of course, some loss of refrigerant from the refrigerant source will occur during use of the aforementioned inlet valve and bleed arrangement but this may be tolerated if the bleed is not too heavy.

A modified form of the invention which may be used to adjust the refrigerant charge in an operating cooling system by either reducing or increasing the charge without loss of refrigerant from the source of refrigerant would include a second thermostatic valve which may be termed a `bleed valve having its inlet connected to the outlet of the first inlet valve and the suction line of the cooling system and also having its loutlet open to the atmosphere. The temperature responsive control element of the bleed valve is connected in sensing relation to the cooling system suction line similarly tothe temperature responsive control element of the inlet valve. Also the pressure responsive control element of the bleed valve is connected to the inlet and hence the suction line of the cooling system to thus sense the pressure of refrigerant in the suction line. This second bleed valve is arranged and calibrated to operate reversely from the first inlet valve as described in the preceding paragraph so that when there is an excess of charge in the suction line of the cooling system, the Ableed valve is opened to release the excess charge to the atmosphere while the inlet valve remains closed to prevent loss of refrigerant from the source lof high .pressure refrigerant. When the excess charge of refrigerant in the suction line is bled off so that the refrigerant charge is at the desired value as indicated by its temperature pressure relation in the suction line, the second valve will be closed and by suitably calibrating both the first inlet valve and the second `bleed valve the arrangement may be such that both valves will be closed when the approximate desired char-ge of refrigerant is present in the operating cooling system.

Yet another modified form of the invention provides that a third or blocking valve of thermostatic controlled operation similar to the inlet and bleed valves previously described be adapted -to be connected with its inlet to the source of high pressure refrigerant and its outlet to the inlet of the first or inlet valve. The temperature sensing control element of the blocking valve is arranged to sense ambient or atmospheric temperature While its pressure responsive control is adapted to be connected to the gage port in the liquid line of the operating cooling system. This blocking valve is calibrated and arranged to be closed when the relative pressure in the liquid line and the ambient temperature conditions for the operating cooling system are such as to indicate a maximum charge of the cooling system, so that the blocking valve is closed to prevent passage of refrigerant from the source to the inlet valve even though suction line pressure and temperature conditions sensed by the inlet valve could be such as to cause the inlet valve to be open. Thus, overcharge of the operating cooling system under certain ambient conditions of operation is prevented.

Further objects, features and the attendant advantages of the invention will be apparent with reference to the following specification and drawing in which:

FIGURE l is a diagrammatic view of an operating cooling system with the refrigerant charging apparatus of the invention including only a thermostatic inlet valve connected thereto together With the source of high pressure refrigerant; and

FIG. 2 is a fragmentary diagrammatic view of the modified refrigerant charging apparatus of the invention showing the thermostatic expansion inlet valve, a thermostatic bleed valve and a thermostatic blocking valve as connected to both the suction line and the liquid line of a cooling system which itself is not shown in detail.

Referring first to FIG. l of the drawing, the simpler form of the invention employing only a single thermo static controlled inlet valve will be described. A more detailed showing of the mechanical arrangement of the thermostatic inlet valve 10 is shown by FIG. 2 of the drawing. All of the thermostatic controlled expansion valves as used in the various embodiments of the inven* tion are of a type well known in 1the art and for example may be the thermostatic expansion valve manufactured by the Alco Valve Company of St. Louis, Missouri and identified as their T-Series Thermo Expansion Valves. Each of the thermostatic expansion valves as arranged to be used for either the inlet valve, the bleed valve, or the Iblocking valve is suitably calibrated and arranged operate in a manner as will be more particularly described in the following specification.

Still referring to FIG. 1 of the drawing, an operating cooling system whose refrigerant charge is to be prede-ten mined by the charging apparatus of the invention is shown to include a pump 11, a condensing coil 12, a liquid line 13, an expansion valve or capillary tube 14, an evaporating coil 15, and a suction line 16. The suction line 16 is provided with a gage port 17 and the liquid line 13 is provided with a gage port 18 as is conventional in the art. The gage ports 17, 18 may be used to bleed off excess refrigerant charge or to insert additional refrigerant charge as required and also various testing apparatus may be connected to the gage ports as is Well known to those skilled in the art.

The thermostatic inlet valve 10 of the charging apparatus of the invention is provided with an inlet passage 20 adapted to be connected through the line 21 to a source of refrigerant charge under high pressure 22. The outlet of the thermostatic controlled valve 10 is connected at 23 to the line 24 that is adapted to be connected to the gage port 17 of the suction line 16 as shown. The temperature sensing control element or bulb 25 of the thermostatic inlet valve 10 is adapted to be connected in temperature sensing relation to the -suction line 16 of the operating cooling system as shown. The pressure responsive control element of the thermostatic inlet valve 10 is connected at 26 to the line 24 also adapted to be connected to the gage port 17 of the suction line 16 as shown in a manner to sense the pressure of the refrigerant in the suction line 16 of the operating cooling system.

The thermostatic valve 10 as used for an inlet valve in the refrigerant charging apparatus of the invention is calibrated and arranged and biased to be normally closed and movable to be opened to permit refrigerant from the refrigerant source 22 to pass through its outlet 23 and into `the gage port 17 of the suction line 16 of the cooling system when the temperature pressure characteristics of the refrigerant in the suction line 16 indicate a low charge as sensed by the temperature responsive valve control element 25 and the pressure responsive valve control element connected to the conduit 26 and opposing the bias means in the valve. It is not believed necessary to outline any specific ranges of calibration ofthe operation `for the inlet valve 10 in accordance with refrigerant pressure in the suction line 16 and temperature of the suction line 16 since these parameters are variable and would be determined by the type of refrigeration system being 4. charged and the type of expansion valve or capillary used together with the ambient conditions expected during normal operation. Also it is believed that such calibration parameters would be well known to those skilled in the aft.

Thus far, a simplified system for automatically adding refrigerant to an undercharged refrigeration system dur ing its operation has been described. In the event that there is an excessive charge in the operating cooling system as indicated by the sensed temperature an-d pressure relations in the suction line, the thermostatic controlled inlet valve 10 is operative to remain closed. However, it might be desirable to bleed off the excess charge of refrigerant and for this purpose a valve 30 and controlled leak or bleed 31 to the atmosphere may be provided. It would be only necessary to open the valve 30, allowing excess charge of refrigerant in the suction line 16 to bleed off into the atmosphere until the thermostatic controlled inlet valve 10 opens to permit charging from the source of refrigerant 22 during continued operation of the charging apparatus of the invention for a short period of time thereafter, and assuming the bleed of excess refrigerant through the bleed element 31 to be relatively small, a balance of the desired charge of refrigerant in the operating refrigeration system may be obtained following which lthe Valves 30 and 10 are closed and the charging apparatus of the invention is disconnected from the suction line gage port 17.

Referring now to FIG. 2 of lthe drawing, a modified and somewhat more elaborate form of the invention will -be described in which the charge of refrigerant in the operating cooling system may be predetermined to be a desired value Whether or not excess refrigerant must be bled off from the operating cooling system or additional refrigerant from the source of refrigerant must be `added 4and the arrangement is such that no loss of refrigerant from the source of refrigerant occurs. In this arrangement the thermostatic controlled inlet valve 10 similar to that shown in FIG. 1 is also provided with its outlet adapted to be connected by the tubing 40 to the gage port 41 of the suction line 42 of the operating cooling system, not shown in detail, In the arrangement shown by FIG. 2, the inlet 43 of the thermostatic controlled inlet valve 10 is connected in series iwith a blocking valve 60 to the source of refrigerant under high pressure 61 but it should be understood that the blocking valve may b omitted and the inlet 43 of the inlet valve 1) may be connected directly to the source of refrigerant under high pressure at 61 by the optional duct shown at 62 in dotted lines. Considering now the optional arrangement without the blocking valve 60` which is to be later described, the temperature sensing control element 44 of the inlet valve 10 is connected to the ltemperature sensing bulb 45 adapted to be connected in temperature sensing relation to the suction line 42 of the operating cooling system and the pressure sensitive control element or diaphragm 46 of the inlet valve is adapted to be connected by the duct 47 to the duct 40 and the gage port 41 of the suction line in a manner to sense the pressure ofthe refrigerant in the suction line 42. Itwill be noted that the arrangement `of the inlet valve 10 is such that it is normally biased by the spring 10a to be closed and may be opened to pass refrigerant from the source 22 and its inlet 43 to its outlet 40 and the gage port 41 of the suction line 42 of the operating cooling system when there is insufficient charge of refrigerant in the cooling system.

In addition a thermostatic controlled bleed valve 50 is provided with lits inlet 51 connected by the duct 52 to the duct 40 and the gage port 41 of the suction line 42 of the operating cooling system. The outlet 53 of the therm'ostatic control bleed valve Sil is open to the atmosphere while the pressure responsive control element 54 of the bleed valve 51 is adapted to be connected by the duct 55 to the duct 40 and also the gage port 41 of the Cooling system suction line 42 to be responsive to the pressure of refrigerant therein. Also the thermostatic Vresponsive control element '6 of the bleed valve 50 is connected to the same temperature sensing bulb 4S as is the thermostatic control element 44 for the inlet valve 10. Therefore the thermostatic controlled bleed valve 50 is arranged to sense both the temperature and pressure relations of the refrigerant in the suction line 42. The bleed valve 50, however, is arranged to ope-rate reversely from the inlet valve and is normally biased to be closed but is calibrated to respond such that the spring 50a will be opposed and the valve will be opened to bleed'excess refrigerant from the gage port 41 through its inlet 51 to its outlet 53 and to the atmosphere only when the temperature pressure relations sensed by the bleed valve 50 are such as to indicate an excess of refrigerant charge in the suction line 42. By suitably calibrating both the inlet valve 10 and the bleed valve 50 and their operation, it is possible to provide that both the inlet valve 10 and the bleed valve 50 will be closed when the approximate desired -amount of refrigerant charge in the suction line 42 is obtained as indicated by the relative pressurerelations of the refrigerant in the suction line 42 sensed by temperature and pressure responsive control elements of the valves 10 and 50.

Under certain conditions of ambient operation the temperature pressure relationship of the refrigerant in the suction line 42 of the operating cooling system might be such as to cause the inlet valve 10 to be opened to permit further charging of refrigerant from the source of refrigerant 61 when actually there is -an adequate charge of refrigerant in the operating cooling system under the ambient conditions being encountered. In order to prevent an excessive charge of refrigerant under such ambient conditions, a third thermostatic controlled valve which may be termed a blocking valve 60 may be provided to prevent passage of refrigerant from the source of refrigerant 61 to the inlet valve 10'. The thermostatic controlled blocking valve 60 is similar to the previously described valves 10 and 50 except for its calibration and manner of operation. In the case of the blocking valve 60 its pressure responsive control diaphragm 63 is adapted to be connected by the line 64 to gage port 65 of the liquid line -66 -of the operating cooling system or to any high pressure line of the cooling system such as the discharge line from the compressor 11. Also in the case of the thermostatic controlled blocking valve 60 its temperature responsive control element 67 is connected to the temperature sensing bulb 68 which is arranged to sense the Iambient or atmospheric temperature conditions in the vicinity -of the operating cooling system such as the condenser cooling air. The inlet of the blocking valve 60 is adapted to be connected at `69 to the source of refrigerant under high pressure 22 by the line 61 and its outlet 70 is adapted to be connected to the inlet 43 of the inlet valve 10 previously described. The blocking valve is normally biased to be open by Vthe spring `60a but is calibrated and -arranged to operate such that when the pressure of the refrigerant in the liquid line 66 as sensed at its gage port l65 in relation to the ambient atmospheric temperature sensed by the temperature sensing bulb 68 `is such as to indicate an adequate charge of refrigerant in the operating cooling system, the blocking valve spring 60a will be opposed to cause the valve to be lclosed to prevent passage of refrigerant from the source 22 to the inlet valve 10 even though the inlet valve 10 may be open because of the temperature pressure relation of the refrigerant sensed by it in the suction line 42 of the operating cooling system.

Various modifications ywill occur to those skilled in the art and it should be understood that the invention is not limited to any particular mechanical arrangement of thermostatic expansion valve nor to any particular calibrated ranges of operation for the valves 10, 50 and 60 since such ranges of calibrations will vary for the different types of cooling systems with which the charging apparatus of the invention may be used. For example, as defined by some yof the appended claims, various combinations of the inlet valve 10 with bleed valve 50 and the blocking valve 60 may be used such as the blocking valve `60 with only the inlet lvalve 10, or the inlet valve 10 wit-h only the bleed v-alve`50.

We claim as our invention:

1. Refrigerant charging apparatus adapted to be detachably connected to a source of refrigerant for predetermining the charge of refrigerant in an operating expansion cooling system of the type containing a refrigerant and having a suction line gage port and a liquid line gage port comprising: valve means including an inlet valve, and a blocking valve; each of said inlet and blocking valves being thermostatically controlled and having inlet and outlet ports together with a thermal control means and bias means including pressure responsive means for opening and closing the respective valve in accordance with relative conditions of temperature and pressure sensed by the respective valve; means adapted to detachably connect the inlet port of said blocking valve to a source of refrigerant; means adapted to detachably connect the pressure responsive means of said blocking valve to the gage port of the liquid line of an operating cooling system; the thermal control means of said blocking valve being responsive -to ambient atmospheric temperature whereby said valve is closed to prevent passage of refrigerant from the source of refrigerant when the pressure in said liquid line is a predetermined value for a related ambient atmospheric temperature; means connecting .the inlet port of said inlet valve to the outlet port of said blocking valve; means adapted to detachably connect the outlet port of said inlet valve to the suction line gage port of an operating cooling system; means connecting the pressure responsive means of said inlet valve to the outlet port of said inlet valve; and means adapted to detachably connect the thermal control means of said inlet valve to the suction line of the cooling system in temperature sensing relation whereby said valve is open when the temperature of said suction line is a predetermined value for a related pressure in the suction line as sensed by the pressure responsive means of said inlet valve to thereby pass refrigerant from said source and blocking valve into the suction line of the operating cooling system until the temperature of the suction line is a predetermined value `for a related pressure in the suction line.

2. The invention of claim 1 in which a bleed passage is connected to the outlet port of said inlet valve whereby excess refrigerant in the cooling system may 'be bled into the atmosphere.

3. Refrigerant charging apparatus adapted to be detachably connected to a source of refrigerant for predetermining the charge of refrigerant in an operating expansion cooling system of the type containing a refrigerant v and having a suction line gage port land a liquid l-ine gage port comprising: valve means including an inlet valve, a bleed valve, and a blocking valve; each of said inlet, bleed, and yblocking valves being thermostatically controlled and 4having inlet and outlet ports together with a thermal control means opposed by bias 4means including pressure responsive means for opening and closing the respective valve in accordance with relative conditions of temperature and pressure sensed by the respective valve; means adapted to detachably connect the inlet port of said blocking Valve to a source of refrigerant; means adapted to detachably connect the pressure responsive means of said blocking valve to the gage port of the liquid line of the operating cooling system; the thermal control means of said blocking valve being responsive to ambient atmospheric temperature whereby said valve is closed to prevent passage of refrigerant from, the source of refrigerant when the pressure in said liquid line of the operating cooling system is a predetermined value for a related ambient atmospheric temperature; means connecting the 7- inlet port of said inlet valve to the outlet port of said .blocking valve; means adapted to detachably connect the outlet port of said inlet valve to the suction line gage port of the operating cooling system; means connecting the pressure responsive means of said inlet valve to the outlet port, of said inlet valve; means adapted to detachably connect the thermal control means of said inlet valve to the suction line of the operating cooling system in temperature sensing relation wherebysaid valve is open when the temperature of said suction line is a predetermined value for a related pressure in the suction line as sensed by the 'pressure responsive means of said inlet valve; means adapted to detachably connect the inlet port of said 'bleed valve to the suction line gage port of the operating cooling system; means adapted to detachably connect the pressure responsive meansvof said bleed valve to the inlet port of said bleed valve; the outlet port of said bleed valve being open to atmosphere; and means adapted to detachably connect the thermal control means for said bleed valve in temperature sensing relation to the suction line of the operating cooling system whereby said bleed valve is open to bleed excess refrigerant from the system-.into the atmosphere when the temperature ofthe suction line in the operatingvcooling system is a predetermined value for a related pressure in the suction line as sensed by the pressure responsive control means ofsaid `bleed Valve.

References Cited bythe Examiner UNITED STATES, PATENTS 2,359,595 10/1944 Urban 62-,149 2,689,463 9/1954 Arf 62-149 X 2,951,349 9/1960 Etherington 62-77 x 2,951,350 9/1960 Etherington et al. 62-292 X LLOYD Lt KING? Primary Examiner.- 

1. REFRIGERANT CHARGING APPARATUS ADAPTED TO BE DETACHABLY CONNECTED TO A SOURCE OF REFRIGERANT FOR PREDETERMINING THE CHARGE OF REFRIGERANT IN AN OPERATING EXPANSION COOLING SYSTEM OF THE TYPE CONTAINING A REFRIGERANT AND HAVING A SUCTION LINE GAGE PORT AND A LIQUID LINE GAGE PORT COMPRISING: VALVE MEANS INCLUDING AN INLET VALVE, AND A BLOCKING VALVE; EACH OF SAID INLET AND BLOCKING VALVES BEING THERMOSTATICALLY CONTROLLED AND HAVING INLET AND OUTLET PORTS TOGETHER WITH A THERMAL CONTROL MEANS AND BIAS MEANS INCLUDING PRESSURE RESPONSIVE MEANS FOR OPENING AND CLOSING THE RESPECTIVE VALVE IN ACCORDANCE WITH RELATIVE CONDITIONS OF TEMPERATURE AND PRESSURE SENSED BY THE RESPECTIVE VALVE; MEANS ADAPTED TO DETACHABLY CONNECT THE INLET PORT OF SAID BLOCKING VALVE TO A SOURCE OF REFRIGERANT; MEANS ADAPTED TO DETACHABLY CONNECT THE PRESSURE RESPONSIVE MEANS OF SAID BLOCKING VALVE TO THE GAGE PORT OF THE LIQUID LINE OF AN OPERATING COOLING SYSTEM; THE THERMAL CONTROL MEANS OF SAID BLOCKING VALVE BEING RESPONSIVE TO AMBIENT ATMOSPHERIC TEMPERATURE WHEREBY SAID VALVE IS CLOSED TO PREVENT PASSAGE OF REFRIGERANT FROM THE SOURCE OF REFRIGERANT WHEN THE PRESSURE IN SAID LIQUID LINE IS A PREDETERMINED VALUE FOR A RELATED AMBIENT ATMOSPHERIC TEMPERATURE; MEANS CONNECTING THE INLET PORT OF SAID INLET VALVE TO THE OUTLET PORT OF SAID BLOCKING VALVE; MEANS ADAPTED TO DETACHABLY CONNECT THE OUTLET PORT OF SAID INLET VALVE TO THE SUCTION LINE GAGE PORT OF AN OPERATING COOLING SYSTEM; MEANS CONNECTING THE PRESSURE RESPONSIVE MEANS OF SAID INLET VALVE TO THE OUTLET PORT OF SAID INLET VALVE; AND MEANS ADAPTED TO DETACHABLY CONNECT THE THERMAL CONTROL MEANS OF SAID INLET VALVE TO THE SUCTION LINE OF THE COOLING SYSTEM IN TEMPERATURE SENSING RELATION WHEREBY SAID VALVE IS OPEN WHEN THE TEMPERATURE OF SAID SUCTION LINE IS A PREDETERMINED VALUE FOR A RELATED PRESSURE IN THE SUCTION LINE AS SENSED BY THE PRESSURE RESPONSIVE MEANS OF SAID INLET VALVE TO THEREBY PASS REFRIGERANT FROM SAID SOURCE AND BLOCKING VALVE INTO THE SUCTION LINE OF THE OPERATING COOLING SYSTEM UNTIL THE TEMPERATURE OF THE SUCTION LINE IS A PREDETERMINED VALUE FOR A RELATED PRESSURE IN THE SUCTION LINE. 